• Korean Journal of Microbiology
• /
• v.50 no.3
• /
• pp.173-178
• /
• 2014

We have developed a method for the preparation of dispersed cell suspensions of Chondromyces crocatus, which is essential for quantitative studies of fruiting body formation. Cells of C. crocatus have a tendency to aggregate in liquid, hindering quantitative studies. However, cells grown on casitone-yeast extract agar plates, containing 3% agar, allowed the preparation of well-dispersed cell suspensions. Cell suspensions at a concentration of $2{\times}10^8cells/ml$, obtained by using this method, developed typical C. crocatus fruiting bodies when placed as $20{\mu}l$ spots on agar plates with no nutrient supplementation. The addition of nutrients such as casitone altered or inhibited fruiting body formation. Fruiting body branch formation increased with increasing agar content. Under optimum conditions, the formation of fruiting body structure in C. crocatus KYC2823 was completed within 24 h.

• Journal of Mushroom
• /
• v.2 no.2
• /
• pp.45-48
• /
• 2004

The effect of $CO_2$ concentration (500, 3,000, $6,000{\mu}{\ell}/{\ell}$) on the mycelial growth and fruit body primordium formation of Ganoderma lucidum on nutrient agar medium was examined. Optimum $CO_2$ concentration for vegetative growth was above $3,000{\mu}{\ell}/{\ell}$. Fruit body initiation was accelerated at higher than $3,000{\mu}{\ell}/{\ell}$ $CO_2$ exposure but the maximum number and size of primordia, and primordium color were not influenced by $CO_2$ concentrations. Whereas each atypical fruiting structure forming stock culture showed different fruiting time under each concentration of $CO_2$ exposure.

• Korean Journal of Environmental Agriculture
• /
• v.17 no.3
• /
• pp.279-285
• /
• 1998

Fenitrothion-degrading microorganisms were isolated from 124 sampling sites of paddy, upland, forest and polluted soil, and wastewater. A total of 1,071 strains were isolated from each selective medium supplemented with 50mg/l of fenitrothion - nutrient agar (NA) 601, potato dextrose agar (PDA) 201, Actinomycetes isolation agar (AIA) 168 and basal salt medium (BSM) 101, respectively. Twenty-eight effective strains of them, which showed more than 80% degradation of fenitrothion by the gasliquid chromatography(GLC) analysis. were successfully selected from each liquid culture supplemented with 50mg/l of fenitrothion - NB 12(upland soil 3, paddy soil 3, forest soil 2, polluted soil 4), PDB 8(upland soil 1, paddy soil 2, forest soil 2, polluted soil 3) and PSB 8(upland soil 1, forest soil 1, polluted soil 6), respectively. Four strains - NPal, NFol, PFol and BPol, which have the most powerful degradation activity were finally selected among 28 fenitrothion-degrading microorganisms based on the degradation rate at the concentration of 100mg/l fenitrothion in enrichment media.

• Journal of Applied Biological Chemistry
• /
• v.52 no.4
• /
• pp.157-162
• /
• 2009

An agar-liquefying bacteria (SC-22), which produces a diffusible agarase that caused agar softening around the colony was isolated from Daecheong lake in Korea. Chemotaxanomic and phylogenetic analyses based on 16S rRNA gene sequences revealed the strain was classified as Cellvibrio mixtus SC-22. The isolate SC-22 showed maximal extracellular agarase activity with 58.5 U/mL after 48 h cultivation in the presence of 0.2% agar. It was observed that the isolate produced two kinds of extracellular and three kinds of intracellular isoenzymes. The major agarase was purified from the culture filtrate of agarolytic bacteria by ammonium sulfate precipitation, anion exchange and gel filtration column chromatographic methods. The molecular mass of the purified enzyme was estimated to be 25 kDa by SDS-PAGE. The optimum pH and temperature of the purified enzyme were pH 7.0 and $50^{\circ}C$, respectively. The agarase activity was activated by $Fe^{2+}$, $Na^+$ and $Ca^{2+}$ ions while it was inhibited by $Hg^{2+}$, $Mn^{2+}$ and $Cu^{2+}$ at 1 mM concentration. The predominant hydrolysis product of agarose by the enzyme was galactose and disaccharide on TLC, indicating the cleavage of $\beta$-1,4 linkage in a random manner. The enzyme showed high substrate specificity for only agar and agarose among various polysaccharides.

• Applied Biological Chemistry
• /
• v.22 no.2
• /
• pp.91-96
• /
• 1979

Several herbs were tested for their antimicrobial activities during preservation of soy sauces. The herbs which resulted in retarded growth of film yeasts were extracted and added to various media such as koji-extract agar, buion-peptone agar to elucidate effects on the growth of film yeasts, Aspergillus oryzae and Bacillus subtilis. The results obtained were as follows: 1) Addition of phellodendron powder resulted in retarded formation of film in fermented soy sauces. Film was produced after 2 days without addition of the phellodendron powder. However, formation of film was observed after 8 days when 0.5 per cent of the phellodendron powder was added, and after 12 days when 1.0 per cent of the powder was added to fermented soy sauce. 2) For the amino acid soy sauce, formation of film was retarded for 6 days by 0.5 per cent of the pow der and for 8 days by 1.0 per cent of the powder. 3) Repression of film yeasts by addition of helenii and camphora powder was recognized respectively, but other herbs were appeared to have no detectable effects. 4) Growth of film yeast and Asp. oryzae way, retarded for 5 days on koji-extract agar plates which contain 0.5 per cent of phellodendron extract. Bac. subtilis also showed retarded growth for 5 days on buion-peptone agar plates containing the same amount of the extract. 5) Retarded growth of film yeast for 5 days was obtained when grown on koji-extract agar plates containing 15 per cent of sodium chloride and 0.3 per cent of phellodendron powder, however, no growth of Asp. oryzae was obtained on this concentration of sodium chloride. Growth of Bac. subtilis was repressed for 5 days on buion-peptone agar plates which contain 15 per cent of sodium chloride and 0.1 per cent of phellodendron powder.

• Korean journal of applied entomology
• /
• v.62 no.3
• /
• pp.139-147
• /
• 2023

Leaf-spray in vitro bioassays appraise new aphicidal formulations for managing deleterious plant-feeding aphids. The formulation may utilize alternative and integrated strategies. However, leaf spraying even under controlled conditions may affect aphid reproduction and mortality. This study examines leaf spray applications for optimum and reproducible aphicidal results using tobacco leaves overlaid on cotton fabric or water agar surfaces. Infestation of the undersides of tobacco leaves with nymphs of green peach aphids was used in the assays. Spray distance and volume were optimized using water-sensitive paper to ascertain the best surface coverage. Overlays of the leaves on water agar caused less mortality and greater reproduction than the use of cotton fabric. The relative humidity of the insect-rearing chambers changed with the watering regime for the insect - rearing chambers with cotton fabric; 60% relative humidity was optimal. Relative humidity was not affected by the concentration of agar in the water agar chambers. Applications of the chemical aphicidal standard, Sulfoxaflor, under the optimized conditions exhibited similar times for lethality although the rate was faster with leaves on the cotton fabric than on water agar. These studies establish reproducible and sensitive techniques for assessing the lethality and effects on reproduction of potential aphicidal products.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.34 no.1
• /
• pp.89-94
• /
• 2010

Patterning bacteria and cells on substrates has potential applications in molecular biology, antimicrobial drug screening, environmental monitoring and tissue engineering. We developed a technique to deposit two-dimensional array of bacterial cells onto an agar plate by modifying commercially available thermal inkjet printers. The concentration of the bacterial solution in the cartridge was carefully determined to ensure a single cell suspension in a droplet ejected from a nozzle. We measured quantitatively the effects of the bacterial concentration and the agar concentration on patterning performance. Bacterial patterning by inkjet printer is a low-cost and versatile technique which may replace the existing sophisticated methods.

• Nutrition Research and Practice
• /
• v.9 no.1
• /
• pp.11-16
• /
• 2015

BACKGROUND/OBJECTIVES: Perilla frutescens Britton leaves are a commonly consumed vegetable in different Asian countries including Korea. Cancer is a major cause of human death worldwide. The aim of the current study was to investigate the inhibitory effects of ethanol extract of perilla leaf (PLE) against important characteristics of cancer cells, including unrestricted growth, resisted apoptosis, and activated metastasis, using human cancer cells. MATERIALS/METHODS: Two human cancer cell lines were used in this study, HCT116 colorectal carcinoma cells and H1299 non-small cell lung carcinoma cells. Assays using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide were performed for measurement of cell growth. Soft agar and wound healing assays were performed to determine colony formation and cell migration, respectively. Nuclear staining and cell cycle analysis were performed for assessment of apoptosis. Fibronectin-coated plates were used to determine cell adhesion. RESULTS: Treatment of HCT116 and H1299 cells with PLE resulted in dose-dependent inhibition of growth by 52-92% (at the concentrations of 87.5, 175, and $350{\mu}g/ml$) and completely abolished the colony formation in soft agar (at the concentration of $350{\mu}g/ml$). Treatment with PLE at the $350{\mu}g/ml$ concentration resulted in change of the nucleus morphology and significantly increased sub-G1 cell population in both cells, indicating its apoptosis-inducing activity. PLE at the concentration range of 87.5 to $350{\mu}g/ml$ was also effective in inhibiting the migration of H1299 cells (by 52-58%) and adhesion of both HCT116 and H1299 cells (by 25-46%). CONCLUSIONS: These results indicate that PLE exerts anti-cancer activities against colon and lung cancers in vitro. Further studies are needed in order to determine whether similar effects are reproduced in vivo.

• Korean Journal of Environmental Biology
• /
• v.21 no.2
• /
• pp.216-221
• /
• 2003

Various physico-chemical and biological methods have been used to remove. cyanobacteria which causes blooms and releases toxin. The purpose of the following experiment is aimed finding out which cyanobacteria are affected by $_L-lysine $ and what concentration of$_L-lysine $ inhibits cyanobacteria. The 20 samples of Microcystis sp. have been tested. To prove the growth inhibition on Microcystis sp., double-layered agar method and microplate method have been used. When the concentration of $_L-lysine $ is as heavy as 100 ${\mu}g\; ml^{-1}$~300 ${\mu}g\; ml^{-1}$, some Microcystis sp. have made halo zone. Some Microcystis sp. have shown so high activity as to be inhibited in their growth by the $_{L}$-lysine of concentration 10 ${\mu}g\; ml^{-1}$ with microplate method. These activities are various in accordance with every species. In additions, the microplate method has been proven to be an easy way which examine the lytic activity on the species of algae.e.

• Journal of Food Hygiene and Safety
• /
• v.26 no.4
• /
• pp.361-365
• /
• 2011

To evaluate the indoor air quality of food manufacturing plants, the presence of viable bacteria and fungi was assessed in the indoor air of the facilities at which 9 food items were manufactured. Air samples were collected from the general zone, low clean zone and clean zone of each factory with an air sampler, in combination with plate counts agar using for bacteria, and dichloran-glycerol agar for fungi. The samples were incubated at $25^{\circ}C$ for 4 to 7 days. After culture, the colony forming units (CFU) on each plate were counted and corrected with a positive hole conversion table. The average concentration of bacteria was $2.2{\times}10^3\;CFU/m^3$ in the general zone, $1.2{\times}10^3\;CFU/m^3$ in the low clean zone and $7.3{\times}10^2\;CFU/m^3$ in the clean zone. The average concentration of fungal microbes was $2.5{\times}10^3\;CFU/m^3$ in the general zone, $2.6{\times}10^3\;CFU/m^3$ in the low clean zone, and $2.0{\times}10^2\;CFU/m^3$ in the clean zone. No meaningful differences were detected between the general zone and the low clean zone, but the clean zone had significantly lower concentrations than the other zones. Additionally, the identification of the fungi was performed according to morphological method using a giant culture and slide culture. The fungi were identified as belonging to 18 genera, and the genera Cladosporium(33%), Penicillium(29%) and Aspergillus(26%), predominated. Aspergillus isolates were identified to species level, and A. ochraceus, a mycotoxigenic species, was identified. As part of the effort to control the quality of the indoor air of food manufacturing plants, our results show that continued studies are clearly warranted.